Question: Name the Class IB flammable liquid with highest density?
Paraphrase: Which flammable liquid is considered Class IB and also has the highest density?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q21009055 . ?ent wdt:P2054 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: Ethanol, acrolein, iron pentacarbonyl, iron pentacarbonyl, bromoethane